From 01ba47d7b6c0dfabb9014e6d904b71e55f0428ed Mon Sep 17 00:00:00 2001 From: Richard Smith Date: Fri, 13 Apr 2012 00:45:38 +0000 Subject: Implement the missing pieces needed to support libstdc++4.7's : __atomic_test_and_set, __atomic_clear, plus a pile of undocumented __GCC_* predefined macros. Implement library fallback for __atomic_is_lock_free and __c11_atomic_is_lock_free, and implement __atomic_always_lock_free. Contrary to their documentation, GCC's __atomic_fetch_add family don't multiply the operand by sizeof(T) when operating on a pointer type. libstdc++ relies on this quirk. Remove this handling for all but the __c11_atomic_fetch_add and __c11_atomic_fetch_sub builtins. Contrary to their documentation, __atomic_test_and_set and __atomic_clear take a first argument of type 'volatile void *', not 'void *' or 'bool *', and __atomic_is_lock_free and __atomic_always_lock_free have an argument of type 'const volatile void *', not 'void *'. With this change, libstdc++4.7's passes libc++'s atomic test suite, except for a couple of libstdc++ bugs and some cases where libc++'s test suite tests for properties which implementations have latitude to vary. llvm-svn: 154640 --- clang/lib/Frontend/InitPreprocessor.cpp | 40 +++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'clang/lib/Frontend/InitPreprocessor.cpp') diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp index c1b9d57..93d49b0 100644 --- a/clang/lib/Frontend/InitPreprocessor.cpp +++ b/clang/lib/Frontend/InitPreprocessor.cpp @@ -202,6 +202,20 @@ static void DefineExactWidthIntType(TargetInfo::IntType Ty, ConstSuffix); } +/// Get the value the ATOMIC_*_LOCK_FREE macro should have for a type with +/// the specified properties. +static const char *getLockFreeValue(unsigned TypeWidth, unsigned TypeAlign, + unsigned InlineWidth) { + // Fully-aligned, power-of-2 sizes no larger than the inline + // width will be inlined as lock-free operations. + if (TypeWidth == TypeAlign && (TypeWidth & (TypeWidth - 1)) == 0 && + TypeWidth <= InlineWidth) + return "2"; // "always lock free" + // We cannot be certain what operations the lib calls might be + // able to implement as lock-free on future processors. + return "1"; // "sometimes lock free" +} + /// \brief Add definitions required for a smooth interaction between /// Objective-C++ automated reference counting and libstdc++ (4.2). static void AddObjCXXARCLibstdcxxDefines(const LangOptions &LangOpts, @@ -521,6 +535,32 @@ static void InitializePredefinedMacros(const TargetInfo &TI, else Builder.defineMacro("__GNUC_STDC_INLINE__"); + // The value written by __atomic_test_and_set. + // FIXME: This is target-dependent. + Builder.defineMacro("__GCC_ATOMIC_TEST_AND_SET_TRUEVAL", "1"); + + // Used by libstdc++ to implement ATOMIC__LOCK_FREE. + unsigned InlineWidthBits = TI.getMaxAtomicInlineWidth(); +#define DEFINE_LOCK_FREE_MACRO(TYPE, Type) \ + Builder.defineMacro("__GCC_ATOMIC_" #TYPE "_LOCK_FREE", \ + getLockFreeValue(TI.get##Type##Width(), \ + TI.get##Type##Align(), \ + InlineWidthBits)); + DEFINE_LOCK_FREE_MACRO(BOOL, Bool); + DEFINE_LOCK_FREE_MACRO(CHAR, Char); + DEFINE_LOCK_FREE_MACRO(CHAR16_T, Char16); + DEFINE_LOCK_FREE_MACRO(CHAR32_T, Char32); + DEFINE_LOCK_FREE_MACRO(WCHAR_T, WChar); + DEFINE_LOCK_FREE_MACRO(SHORT, Short); + DEFINE_LOCK_FREE_MACRO(INT, Int); + DEFINE_LOCK_FREE_MACRO(LONG, Long); + DEFINE_LOCK_FREE_MACRO(LLONG, LongLong); + Builder.defineMacro("__GCC_ATOMIC_POINTER_LOCK_FREE", + getLockFreeValue(TI.getPointerWidth(0), + TI.getPointerAlign(0), + InlineWidthBits)); +#undef DEFINE_LOCK_FREE_MACRO + if (LangOpts.NoInlineDefine) Builder.defineMacro("__NO_INLINE__"); -- cgit v1.1